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