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