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