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