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