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)(19,23)(21,24)(25,26,30,31)(27,28,33,32)(29,34,37,39)(35,36,40,38)(1,2,5,3)(4,7,8,6)(9,10,14,12)(11,15,13,16)(17,18,20,22)(19,21,23,24)(26,31)(27,33)(29,37)(36,38)(2,3)(6,7)(9,11,14,13)(10,15,12,16)(17,18)(19,21)(20,22)(23,24)(25,27,30,33)(26,32,31,28)(29,35,37,40)(34,38,39,36)(1,3,5,2)(4,7,8,6)(9,12,14,10)(11,15,13,16)(17,19)(18,21)(20,23)(22,24)(25,28,30,32)(26,33,31,27)(29,38,37,36)(34,35,39,40)(1,4,5,8)(2,6,3,7)(9,13,14,11)(10,15,12,16)(17,19)(18,21)(20,23)(22,24)(25,29)(26,34)(27,35)(28,36)(30,37)(31,39)(32,38)(33,40)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.