What type of colored pencils do you have that would be good to draw on rocks

Check with an associate who works there. The medium doesn't sound like something you would want to use.

Have all different markers and permanent pens there to use

Colored pencils don't work. Patio or outside paint works best.

I dont think colored pencils would be the best choice to draw on rocks. Typically people use perm markers like Sharpies or paints.

I'm not for sure but I am sure they have something that would work