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