For example :

1.You are a graduate of the University.

We always use "of" with the noun,not "from" in that context.

2. You graduated from the University.

But with the verb, we use from.

You can't say 'graduated of'. Graduated from..XYZ University - verb. A graduate of XYZ University - noun.

I have an XYZ degree from XYZ college. I'm a graduate of XYZ.