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