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