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