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