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)(11,18)(12,21)(13,16)(14,17)(15,20)(19,23)(22,24)(26,31)(32,33)(34,38)(39,40)(1,3,5,4)(2,6,7,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,23)(17,18)(21,24)(26,32)(27,30)(28,35)(31,33)(36,37)(39,40)(1,4,5,3)(2,6,7,8)(25,26,29,31)(27,32,30,33)(28,34,36,38)(35,39,37,40)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(25,27,29,30)(26,33,31,32)(28,35,36,37)(34,40,38,39)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,28)(26,34)(27,35)(29,36)(30,37)(31,38)(32,39)(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.