They separately report people who are on unemployment insurance, but the headline unemployment numbers come from a survey of potential workers, which will capture recent graduates.

Source: 15 years ago I was one of the people they surveyed. Every month for a year they called me, once a month, to ask what my employment status last week was, if I was actively looking, etc. (It was all synchronized around one week a month, but I don't remember which one it was they cared about.)