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