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)(25,26,32,34,31,35,30,29)(27,36,40,33,38,39,37,28)(1,3,4,7)(2,5,6,8)(11,18)(12,21)(14,17)(15,20)(25,27,31,38)(26,33,35,28)(29,39,34,36)(30,40,32,37)(2,6)(5,8)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(25,28,31,33)(26,27,35,38)(29,37,34,40)(30,39,32,36)(11,18)(14,17)(19,24)(22,23)(25,29,30,35,31,34,32,26)(27,28,37,39,38,33,40,36)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(25,30,31,32)(26,34,35,29)(27,37,38,40)(28,36,33,39)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.