If you can’t get the cached version the good old fashioned way by typing cache:www.example.com into Google search for some reason (other than the page not being indexed or having the noarchive tag), use this URL:
https://webcache.googleusercontent.com/search?q=cache:https://www.example.com
If you want the text version of the cache, add &strip=1 to the end like so:
https://webcache.googleusercontent.com/search?q=cache:https://www.example.com&strip=1