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