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