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