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