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