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