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