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