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)(27,33,35,31)(28,32,37,38)(34,40,36,39)(1,2,6,5)(3,7,8,4)(10,13)(14,16)(26,30)(31,33)(32,38)(39,40)(1,3,6,8)(2,7,5,4)(9,10)(11,14)(12,13)(15,16)(17,18,21,22)(19,23,20,24)(25,27,29,35)(26,31,30,33)(28,36,37,34)(32,40,38,39)(1,4)(2,3)(5,8)(6,7)(17,19,21,20)(18,23,22,24)(25,26)(27,31)(28,32)(29,30)(33,35)(34,39)(36,40)(37,38)(1,5,6,2)(3,4,8,7)(9,11)(10,14)(12,15)(13,16)(17,20,21,19)(18,24,22,23)(25,28,29,37)(26,32,30,38)(27,34,35,36)(31,39,33,40)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.