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