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