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