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