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