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