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