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