Here is my script for drawing stat graphs within GameMaker.
This script uses a ds_list of values to create the polygons needed for the graph with options to input colours, rotation, stat names and a few other arguments. Contained within is a breakdown for each of the scripts arguments and if anything is unclear I will be happy to help.
Please note: The section of the script that draws the stat names to the corresponding points on the graph won't necessarily work if your font size is too large. If the code is not accustom to the style of font and spacing you wish to use a more precise text drawing method may be required. To stop the script from trying to draw text set the content in the statNames unidentified or blank strings.
The script will set the halign and valign variables during the drawing process so I recommended that you re-establish them after the script is used.
Examples of my work can be viewed at: https://www.youtube.com/user/Solidival