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