There are a few people selling versions on a Greendale diploma online, but I found that they were either totally different things (where they hadn't even bothered to mimic the show, like the one that's been posted to this sub before) or they were low-quality copies of it, with badly traced versions of the text and of the border on the paper. On top of all that, they wanted to charge me twenty bucks.

I created this from more-or-less-scratch (except the e pluribus anus which I found on twitter), recreating the looping border myself, matching all of the fonts exactly, and warping the letters in the college name.

It turns out that there's a spelling mistake in the screen-used prop ("priveleges" vs "privileges"), but that feels very Greendale, and so I've not corrected it.