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