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