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