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