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