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