A clean, well-lighted café, somewhere in Spain (we think)
The setting is key here, especially since we have very little else to go on. The café is – as you might imagine, clean. Oh yeah, and well-lighted. It's a pleasant café, and the light creates the shadows of leaves at night. The story is set late at night, and the café is quiet; only the two waiters and a single customer, the old man, sit there. Other than that, we actually don't know anything about the place. We can guess that it's in Spain, or at least in a Spanish-speaking country (Hemingway had a real thing for Spain, especially at this point in his life, so that's our guess). The location doesn't matter, though – actually, nothing else matters. This café could be anywhere, at any time. The specifics aren't important at all, and we just have to know that this is a good place to be on a dark lonely night.
The older waiter also briefly stops at a bar on his way home; the bar, though pleasant and well-lit, isn't clean enough for his liking, and he doesn't linger there, choosing instead to return to his lonely home.