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