The college reading problem
Most college readers have just spent four years reading what other people assigned. The reading-for-pleasure muscle is atrophied. The first books you pick post-college shape whether you become a reader for life or someone who used to read.
Pick a coming-of-age novel that respects your age
Douglas Coupland's Microserfs (1995) is the easy entry point. Funny, smart, finishable in a week, set in a working-life world close enough to early-twenties experience that you recognize the texture. Rita Mae Brown's Rubyfruit Jungle is the harder, better book. Sherman Alexie's True Diary of a Part-Time Indian is the most-read American novel in this slot for a reason.
Pick one literary novel that takes itself seriously
Michael Cunningham's The Hours is the right one. Demanding but not punishing, 226 pages, finishes in a long Saturday. Reads better at twenty-five than it would have at twenty.
Pick one nonfiction book on something you actually want to know about
If you want to be more productive: Atomic Habits. If you are interested in U. S. political history: Bill Clinton's My Life. If you are interested in the internet or computing: Katie Hafner's Where Wizards Stay Up Late, the 1996 history of ARPANET that remains the standard reference. The point is to read nonfiction that does not feel like school.
Build the habit, not the library
The single most important post-college reading practice is finishing books. Not collecting them, not buying them, not having shelves. Finishing them. Pick books you will actually complete in three weeks. Skip anything that drags. The reading-for-pleasure habit is built on completed books, not on noble attempts.