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