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