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