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