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