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