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