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