Elway
...and that's all I've got.
I'm gonna take a wild stab and go with Bart Starr as one of the others. Don't think I can come up with any others, at least not without sitting down and thinking long and hard about it.
The Bus!
Paul Hornung didn't retire after Super Bowl I. Hornung actually signed on the following season with the Saints, but had to retire during training camp because of a neck injury, which is the same reason he didn't play in Super Bowl I.
I only really knew the Elway answer (who doesn't) and forgot about Hornung never actually playing in the 1968 season.
Bill Walsh. (Vince Lombardi, Bill Parcells, Jimmy Johnson and Dick Vermeil each resigned after winning Super Bowls, but each later returned to coaching -- in Parcells's case, three times.)
but not in the NFL
And the WSJ does list Walsh as the answer. In fact, nobody has permanently retired from coaching, period, right after winning a Super Bowl.