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