One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10,16,20,15,22,14,21)(11,19,25,34,24,33,13,17)(12,26,28,37,30,36,29,18)(23,35,39,40,27,32,31,38)(1,2,4,5)(3,6,7,8)(9,11,14,13,15,24,16,25)(10,17,20,19,22,34,21,33)(12,27,29,39,30,23,28,31)(18,32,26,38,37,35,36,40)(3,7)(6,8)(9,12,14,29,15,30,16,28)(10,18,20,26,22,37,21,36)(11,23,13,31,24,27,25,39)(17,32,19,38,34,35,33,40)(1,3,4,7)(2,6,5,8)(9,13,14,24,15,25,16,11)(10,19,20,34,22,33,21,17)(12,27,28,31,30,23,29,39)(18,35,36,38,37,32,26,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.