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