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