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