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