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