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