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