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