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