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