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