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