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