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