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