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