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