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