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