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