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