I don’t know if this has changed in Krita 5 but for now in v4.4.8, I can’t barely distinguish selected nodes from non selected nodes in mesh mode.
I don’t know if it’s just my poor eyes but I think it could be improved. For instance, selected nodes could have a border which color is inverted from the background. Hence, if the node is above a red color, its border would be cyan, and so on. I don’t know the best way to make the best contrast in every situation but you get the idea.