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