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