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