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