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