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