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