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