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