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