Script Summary: On the posting page that shows your tag list, use custom colour for the tag links. Requires you to edit the script file a bit to choose a link colour and a hover colour.
Firefox Configuration Instructions:
1. After installation, open the installed script file for editing. Go to Tools -> Add-ons, and in the Add-ons screen that opens, click User Scripts. You should see a list of all your installed scripts. Right click on the "Pinboard - Change Tag Link Colour in Posting Page" script and choose Edit. The script file should open in a text editor.
2. You'll see a CONFIGURATION section near the top that looks like this:
// ***** CONFIGURATION *****
var linkColor = "#000";
var hoverColor = "red";
3. Replace #000 and red with the colours of your choice.
4. Save the file and load the Pinboad posting page with tags to see if your changes took effect.