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