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