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