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