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