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