It’s not possible in the Graph yet, correct.
But you could click on the central point of that star.
I don’t know if it’s a C
ollection or an Object like a Page, but in both cases you would easily ne able to delete the unwanted Objects then.
Admittedly it’s not easy and user friendly, but you can do it on your own.
See this thread:
And also see this more general and deeper thread:
In the first linked thread our appreciated @MikeyP offers a link to a CSS file that you simply need to place into your work directory (menu, File, Show Directory, Work) and you’ll have nice Tag colours (and some other changes too).
Or take mine (it’s based on his CSS, but solves a problem his one has): custom.zip (1.1 KB)
Unpack the zip file and place the resulting CSS file into your work directory.
Edit: My file works only for dark mode. I’ve removed the settings for the light mode.