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