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