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