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