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