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