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