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