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