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