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