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