I just came across this by accident whilst browsing through some of the directories under the ColdFusion install root.

A common ColdFusion charting question is how to customise styles on charts when you cannot find an appropriate CFCHART tag attribute to do so.

If you're running ColdFusion in standalone mode, navigate to \charting. Now run the webcharts.bat batch file and the webcharts chart customisation application will start. You'll need to have the Java runtime installed for this to work.

You can now pick and choose various chart styles to customise. When you have finished your customisations, switch to the XML Style tab and click the save button. Save the file to the WEB-INF\cfusion\charting\styles directory. You can now make use of your new style by using the name of your file within the CFCHART tag STYLE attribute.

The application can also generate JSP, AWT & swing code, should you want to use Java!

There's a more comprehensive tutorial here.