Where can I get the CD InLay Design Software for this product for my Mac?
The PrinParade software is exactly what you need for your purpose. I have checked the official website and there are guides for the CD-InLay templates. I recommend that you check the official website to find more information about the software and the CD-InLay.
Official website: http://printparade.eu/page/index.php?d=pp%2Fsoftware%2Fstart
Tip: The info can be accessed from the left menu.