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