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