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