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