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)(25,26)(27,30)(28,32)(29,33)(31,36)(34,37)(35,38)(39,40)(9,11,14,20)(10,15,17,18)(12,19,13,22)(16,23,21,24)(27,34)(28,35)(30,37)(31,39)(32,38)(36,40)(2,5)(6,8)(25,27,35,40,29,36,28,34)(26,30,38,39,33,31,32,37)(1,3,4,7)(2,6,5,8)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(27,36)(30,31)(34,40)(37,39)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,27,35,40,29,36,28,34)(26,31,38,37,33,30,32,39)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.