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