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