There was a double for Mike Brown and further tries from Micky Young, Tom Johnson, Billy Twelvetrees, Henry Trinder, Charlie Sharples, replacement Graham Kitchener and Paul Hodgson, plus a penalty try awarded by referee Nigel Owens after the Americans repeatedly collapsed scrums near their own try-line.
The home pack's dominance was underpinned by a fine performance by Matt Stevens, making his return to England colours at tighthead for the first time since serving his two-year ban for cocaine use.
Surprisingly, it was the Americans who took the lead, with Tai Enosa booting an early penalty, but Saxons dominated the first half and indeed the rest of the match thereafter.
A surge from captain Jordan Crane created the chance for Benjamin to cross for his first try and Brown took advantage of sloppy American play to given England early comfort.
Brown kicked through for Benjamin to sprint on and touch down for his second five-pointer, and Young pounced soon afterwards to inflict more pain on former Ireland coach O'Sullivan.
The penalty try moved Saxons 33-3 ahead, and the tries continued to flow after the interval, Brown adding another in the early stages of the second half and Johnson dashing over in fine style before Twelvetrees added his name to the scoresheet.
Trinder and Sharples kept the score ticking over before Kitchener scored one and set up another for Hodgson.
The most scant of consolations arrived late on for the United States as Scott Lavalla darted over. As well as their tries, England had 22 points from goal-kicker Rory Clegg.