From looking around on Google maps, the pink line seems to show the existing roads on the park, I can only assume the purple line is the proposed circuit.
Google Streetview is my new favourite toy, its really handy for scouting out locations for street circuits, and I should point out that from looking around in it none of the existing 'pink' roads appear wide enough to race on. Morris Pesin Drive and Phillip Street (the south and west sides of the square) are two lanes wide, Freedom Way (the east side) is a single lane, and Audrey Zapp Drive to the North is paved with cobblestones! Whatever the final layout, its not as though you're saving any work by using the existing streets since they're all going to have to be torn up and massively widened anyway (unless of course the Streetview images are out of date now).
Here's my first attempt:
http://www.gmap-pedometer.com/?r=3699286