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