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