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