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