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