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