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