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