Hi apurvsrivastav,
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:
http://stackoverflow.com/questions/22439891/d3-sankey-chord-colors
http://stackoverflow.com/questions/13006712/d3-js-sankey-diagram-rectangles-fill-color
http://stackoverflow.com/questions/30614921/changing-the-colour-of-the-node-in-sankey-diagram-using-d3-js-library
Hope this helps ...
cheers, MuS
... View more