As you can see from the picture below, the coloring pages I created are in a sense open-ended. You can have your students copy down words from your articulation deck or worksheets in whatever position they need. This gives them extra practice using those fine motor skills before they get to enjoy the coloring aspect. Students who are at more advanced levels can make up phrases or sentences for each word that they write on an attached sheet of paper, for example.
P.S. If you have coloring perfectionists, I sometimes play a familiar song (Do you want to build a snowman?) as a way to give them an idea of how much time they have to color. I give them a warning in the last 30 and 15 seconds. It doesn't help for all kids, but it's another trick to keep in your toolbox.
Grab your copy of Sounding Boards for Articulation here.