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