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