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