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