Were Feynman diagrams pre-quark? Are Feynman diagrams still in common use?
Yes and Yes.
Feynman diagrams were originally developed for quantum electrodynamics, which doesn’t care about quarks, and that’s still the field where they’re most useful. You can draw the Feynman diagrams for the strong force, and do the calculations, but except in the high-energy limit, you can’t really get results from them, since you’d need an infinite number of diagrams.