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