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