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)(11,18)(12,20)(13,15)(14,23)(16,19)(17,22)(21,24)(1,3,4,8)(2,5,6,7)(10,15)(11,12)(17,23)(19,21)(25,26,29,32)(27,33,35,40)(28,36,38,31)(30,37,39,34)(9,11,13,12)(10,16,15,24)(14,21,22,19)(17,20,23,18)(25,27,29,35)(26,30,32,39)(28,37,38,34)(31,40,36,33)(2,6)(3,8)(9,12,13,11)(10,16,15,24)(14,19,22,21)(17,20,23,18)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.