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