Hi Katryn,
You can easily add a new colour to your color palette. In your case you are using a 100% Magenta hairline as a cutting line. You can create color for your palette bij choosing the “Add spot color…” feature as available under the menu File > Colors > Add spot color…
Select the CMYK color model and put the Magenta bar at 100% (the other colors should be at 0%) and press add to enter the name (eg CutContour). The Color will be added to your palette automatically. If you do not see this immediately please scroll further in the palette with the tool button on the right side of the color palette.
Have an easy day!
Wilbert at EasySIGN