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