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