Looking on the internet deeply has found these results:

graduated from is the most popular phrase on the web.

graduated in 11,180,000 results on the web	graduated from 172,700,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Educated at the neighbouring Benedictine abbey of Cerne and at Balliol College, Oxford, he graduated in law, and followed that profession in the ecclesiastical ... Jan 12, 2015 ... The problem is with the verb: graduated. In this context, it should always take the preposition from. Graduated from. You don't graduate college. Tom graduated in the same year as Mary. (CK); [S] · [T] Tom is thinking about ... Tom graduated in the top ten percent of his class. (CK); [S] · [T] He returned to ... ... degree, course of training, or (in North America) high school: he graduated from Glasgow University in 1990 he graduated in the summer with a 2:2 degree.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

graduated in

11,180,000 results on the web

graduated from

172,700,000 results on the web

More popular!

Educated at the neighbouring Benedictine abbey of Cerne and at Balliol College, Oxford, he graduated in law, and followed that profession in the ecclesiastical ...
Jan 12, 2015 ... The problem is with the verb: graduated. In this context, it should always take the preposition from. Graduated from. You don't graduate college.
Tom graduated in the same year as Mary. (CK); [S] · [T] Tom is thinking about ... Tom graduated in the top ten percent of his class. (CK); [S] · [T] He returned to ...
... degree, course of training, or (in North America) high school: he graduated from Glasgow University in 1990 he graduated in the summer with a 2:2 degree.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.