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)(12,17,20,15)(13,16,22,18)(19,24,21,23)(25,26,31,32)(27,29,28,35)(30,33,39,40)(34,37,36,38)(3,7)(5,8)(10,11)(15,17)(16,18)(23,24)(25,27)(26,29)(28,31)(30,34)(32,35)(33,37)(36,39)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(10,11)(15,17)(16,18)(23,24)(26,32)(27,28)(33,40)(34,36) involution — undirected(1,3,4,7)(2,5,6,8)(9,11,14,10)(12,17,20,15)(13,16,22,18)(19,23,21,24)(25,28,31,27)(26,29,32,35)(30,34,39,36)(33,38,40,37)(1,2)(3,5)(4,6)(7,8)(9,12,14,20)(10,15,11,17)(13,21,22,19)(16,24,18,23)(25,29)(26,27)(28,32)(30,38)(31,35)(33,36)(34,40)(37,39)(9,13,14,22)(10,16,11,18)(12,19,20,21)(15,23,17,24)(25,30,31,39)(26,33,32,40)(27,34,28,36)(29,37,35,38)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.