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