One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,16,21)(11,22,26,34)(12,18,29,37)(13,19,28,38)(14,30,15,20)(17,31,35,25)(23,33,40,36)(24,39,27,32)(9,11,14,25,16,26,15,31)(10,17,20,22,21,35,30,34)(12,27,28,40,29,24,13,23)(18,36,19,32,37,33,38,39)(2,5)(6,8)(9,12,15,13,16,29,14,28)(10,18,20,19,21,37,30,38)(11,23,25,27,26,40,31,24)(17,32,34,36,35,39,22,33)(9,13,15,29,16,28,14,12)(10,19,20,37,21,38,30,18)(11,24,25,23,26,27,31,40)(17,33,34,32,35,36,22,39)(1,3,4,7)(2,6,5,8)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.