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