For whatever reason, I've gotten mixed results with Archive.org. In the past, I thought I was able to save cached pages. Today it said that the site was overloaded and to try again in 600 minutes.
On the other hand, Archive.today works reliably for cached pages. For example, https://archive.ph/x65wT is the archived version of the cache of SQL sanitizing in code with no user input.
Note: It's possible that some pages won't show up in Google's cache at all. Nothing can be done about that except maybe saving the page directly.