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