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