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