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