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