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