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