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