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