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