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