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