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