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