Mark Odejobi scores
Wasps team-mate Mark Odejobi also scored in the victory, with scrum-half Joe Simpson coming off the bench in the second half.
The victory follows an opening day win over Fiji and sets England up for Saturday's final group game against Australia, when the winners will progress to the semi-finals.
England scored nine well-worked tries ' three more than they did against Fiji in the Pool C opener.
Jon Fisher (London Irish) opened the scoring with Matthew Cox (Worcester), Odejobi, Rob Miller (Newcastle Falcons), Luke Eves (Bristol) and captain Ellis also touching down.
Miller added five conversions and a penalty to finish with 18 points and there were two England's two debutants ' Northampton lock Courtney Lawes and London Irish hooker James Clark.
Replacement scrum half Sean White scored the first and flanker Thyssen de Goede the second, an interception gift from England's Ben Thomas.
In terms of raw figures, England surpassed their performance in the first half of the opening game against Fiji. This time they scored seven tries ' five of them in the last 12 minutes ' against a poorly organised defence.
England had laboured through the opening quarter, relying on the superior sharpness of their support play and finishing rather than blowing Canada apart up front.
Fisher was first over the line after Charlie Sharples' long break down the left and cut infield, then Cox was perfectly placed behind Miller to add a second, the fly half converting both and adding a penalty to put his side 17-0 clear in as many minutes.
Canada had made brief forays into the England 22, shunted back when they drove for the line and then missing out when Hirayama knocked on a metre short before getting on the board with a penalty 27 minutes in.
That was the cue for England's best spell, though, with Alex Tait involved in three of the five scores that followed.
The Newcastle centre provided a canny kick behind the cover for Odejobi to touch down, a burst through the middle that ended with Eves going over on the left, and a break and dummy from his own 22 before giving Ellis a 40 metre run to the line.
In between, Youngs made two sharp breaks of his own, the first ending in his own try from 70 metres out, the second in Rob Miller's first England Under 20 try.
Joe Simpson came on for England U20 in the second half
Again, the start of the second half was more frustrating as both sides made changes and the game flattened out, Hirayama adding a second penalty and his side kicking for position.
England stuttered through the third quarter, scoring a second try through Youngs but failing to put away other clear-cut chances. They commanded the lineout, though, with four locks on the field after Fisher and Ellis were withdrawn.
Youngs darted over for his second score, but the game drifted into the last 10 minutes before life was injected into it again, scrum half White going round the blindside to score.
Cato stretched his record for England this season with an eighth try in seven internationals after chasing a kick into the corner and bumping his way past the final tackler.
Canada had the final word, though, a promising attack from deep ending with De Goedie strolling over for a consolation score after picking off a loose pass
England: Noah Cato (Saracens); Mark Odejobi (London Wasps), Luke Eves (Bristol Rugby), Alex Tait (Newcastle Falcons), Charlie Sharples (Gloucester Rugby); Rob Miller (Newcastle Falcons), Ben Youngs (Leicester Tigers); Billy Moss (Bath Rugby), Joe Gray (Northampton Saints), Scott Freer (Leeds Carnegie), Courtney Lawes (Northampton Saints), Gregor Gillanders (Leicester Tigers), Jon Fisher (London Irish), Matthew Cox (Worcester Warriors), Hugo Ellis (London Wasps, captain).
Replacements: James Clark (London Irish) for Gray 53, Alex Corbisiero (London Irish) for Freer 54, Ben Thomas (Saracens) for Ellis 41, Scott Hobson (Cornish Pirates) for Fisher 51, Joe Simpson (London Wasps) for Youngs 64, Miles Benjamin (Worcester Warriors) for Odejobi 53.
Scorers: Tries: Youngs 2, Fisher, Cox, Odejobi, Miller, Eves, Ellis, Cato. Conversions: Miller 6, Penalty: Miller
Canada: Harry Jones; Jordan Wilson-Ross, Michael Scholz, Taylor Dalziel, Kyle Buckley; Nathan Hirayama, Jamie Mackenzie; Andrew Tiedemann, Ryan Hamilton, Mauro Perizzolo, Michael Berg, Struan Robertson, Thyssen de Goede, Keegan Selby, Seb Pearson.
Replacements: Russell Ward for Tiedeman 50, Antoni Wodzicki for Robertson 57, Ian Manly for Selby 38, Sean White for Pearson 57, Matt Evans for Dalziel 41, Conor Trainor for Dalziel 18-27, for Scholz.
Scorers: Tries: White, De Goedie. Conversion: Hirayama. Penalties: Hirayama 2.
Referee: Taizo Hirabayashi (Japan).