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