I want to change the color of the strip between two nodes depending upon the content (display text) of nodes.
So for example if one of the nodes (in Sankey Daigram) has "Error" in its name, then color of strip linked to it must change to RED.
I don't think it's the perfect answer - but I post it as one, because the question is not Splunk related as well 😉
Have a look at the posts I found using a simple google search https://www.google.com/webhp?hl=en#hl=en&q=d3+sankey+change+color+based+on+value , because you must do this in either the sankey.js or using css but not in Splunk itself:
Hope this helps ...