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