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