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