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