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