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