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