How to change size of 'neuron' in graph?

The nodes on my graph view are all the same regardless of how many connections or references there are, which makes analyzing them difficult as it they start to all blend together once you’ve got a lot of notes going. Example I just made:

image

What do if I would to make some of vertex more bigger than others? For example, to highlights more influency theme.
I think, it will be usefull option to have x1.5-x2 size in any page of graph.