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