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