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