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