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