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