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