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