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)(11,17)(12,20)(13,14)(15,19)(16,21)(18,23)(22,24)(25,26)(27,30)(28,36)(29,33)(31,35)(32,38)(34,40)(37,39)(2,5)(3,8)(10,13)(12,21)(15,17)(18,22)(25,27,29,35)(26,30,33,31)(28,37,38,34)(32,40,36,39)(1,3)(2,6)(4,5)(7,8)(9,11,14,19)(10,15,13,17)(12,18,21,22)(16,23,20,24)(25,27)(26,31)(28,34)(29,35)(30,33)(32,40)(36,39)(37,38)(1,4,7,6)(2,3,5,8)(9,11)(10,15)(12,22)(13,17)(14,19)(16,24)(18,21)(20,23)(25,26)(27,30)(28,32)(29,33)(31,35)(34,39)(36,38)(37,40)(1,5,7,2)(3,4,8,6)(9,12)(10,16)(11,18)(13,20)(14,21)(15,23)(17,24)(19,22)(25,27)(26,31)(28,34)(29,35)(30,33)(32,40)(36,39)(37,38)(1,6,7,4)(2,8,5,3)(9,13,14,10)(11,17,19,15)(12,20,21,16)(18,24,22,23)(25,28,29,38)(26,32,33,36)(27,34,35,37)(30,39,31,40)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.