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