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