Links in bases are not displayed in graph

The fact that some notes appear together in a Base does not constitute a link (in the obsidian sense) among those notes or between the base file and those notes.

You can make a FR for this, but to be frank this is unlikely to happen.

There is another FR that is asking to introduce a “local” graph view specific to the base. That feature request is somewhat similar in spirit but different in practice from what you described.