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