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