I disagree with Richard. I fell that for that age group it is a good idea to give them a paintbrush in the selected colour as a 'mouse cursor', to make it clearer to them that they can use their finger/brush to colour things in. I'm just following my gut feeling on this, and can't back it up with any research.

I do agree with Richard that a touch device generally doesn't need a cursor, but should it really be ruled out in this particular example?

Perhaps Penguin will user test this, or already has.