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