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