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