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