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