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