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