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