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