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