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