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