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