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