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