Adobe CQ (AEM) comes with this handy feature called timewarp – in a nutshell, it allows you to see the page in different versions by adding a timewarp cookie or timewarp parameter to your page. Just go to the sidekick and go to the version tab. Expand the timewarp tab. select a date and time and click go (or timewarp to see a modal with a history of the edits.
If you want to access an older version of the page directly, add ?timewarp=(long) as a time to your URL and you should see the older version.
Starting with 5.6, you may want to exit the timewarp before you do anything else. Going back to the new touch UI projects screen while in the timewarp mode throws an exception (the timewarp is by default set as a cookie and filters the repository accordingly, so this may start to fail).
I’d say Adobe has some work to do here – somewhere along the lines of ‘let’s do the timewarp again’