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