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