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