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