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