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