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)(25,26,31,35)(27,32,28,37)(29,34,30,39)(33,36,40,38)(1,2)(3,7)(4,6)(5,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,23)(17,18)(21,24)(25,27,31,28)(26,32,35,37)(29,38,30,36)(33,39,40,34)(1,3,4,8)(2,5,6,7)(25,28,31,27)(26,33,35,40)(29,38,30,36)(32,39,37,34)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,29,31,30)(26,34,35,39)(27,36,28,38)(32,40,37,33)(2,6)(5,7)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(26,35)(32,37)(33,40)(34,39)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.