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