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