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