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