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