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