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