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