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