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