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