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