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)(11,22)(12,27)(13,31)(14,19)(15,21)(16,25)(17,29)(18,33)(20,32)(23,39)(24,37)(26,30)(28,40)(34,35)(36,38) involution — undirected(1,3,4,8)(2,5,6,7)(9,11,23,38,14,27,13,25,15,28,33,37,32,26,34,17)(10,16,35,12,20,36,18,22,21,29,31,30,19,24,39,40)(2,6)(5,7)(9,10)(11,24)(12,25)(13,18)(14,20)(15,21)(16,27)(17,30)(19,32)(22,37)(23,35)(26,29)(28,36)(31,33)(34,39)(38,40) involution — undirected(2,6)(5,7)(9,12,23,36,14,22,13,29,15,30,33,24,32,40,34,16)(10,17,35,11,20,38,18,27,21,25,31,28,19,37,39,26)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.