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