Change node style based on name / label

Question

I'm using vis.js to visualise a network. The network is created based on the DOT language (Directed graphs). An example:

1 -> 1 -> 2; 2 -> 3; 2 -- 4; 2 -> 1

would create this graph / network:

More info about how this works here

My problem is that I want to make a node with a certain label ("1" for example) to be a different color.

Is this possible and how would I do this?