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