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