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