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