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