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