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