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