No "sort of" and no graph-"like", it's just, yes. If you follow symlinks you can have a graph. Many filesystems also permit hard-links to form a graph, which makes it that much trickier for a program to determine if it's in a graph or tree regime; I believe many file systems also deny this.

Symlinks + preventing directory hardlinks are a decent compromise in power, where things that choose to understand them can handle graph-like structures, but things that wish to treat filesystems naively (thus treating symlinks as just another file) can work on trees. Beware the "friendly" library that automatically follows symlinks in something like a scripting language, for they are throwing you to the wolves in the name of user friendliness.