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