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