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