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