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