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