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