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