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