2) Work out some house rules that show mutual respect for each side. Curfews for young adults might not work, but the graduate needs to be respectful of others in the home.
3) The graduate should contribute to the household, by sharing expenses or working around the house.
4) Are there other relatives who might have room? Some grandparents need the company and help around the house. Working out a mutual beneficial agreement could help both sides.
5) Some experts suggest young adults should function like they're still living on their own, doing their own laundry, cleaning, and cooking. Don't expect your parents to revert to childhood patterns.
6) It might also be a good idea to do some redecorating. If you're room hasn't changed since high school graduation, maybe you start the transition to adulthood by turning your space into a place an adult would live.
7) Finally, set goals or milestones that will move the graduate toward a move out date. It could be a time limit, or when their student loans are paid off, or when they have a higher paying job. Agree on some benchmarks that will give both sides some hope that the arrangement will not last forever.