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