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