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