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