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