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