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