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