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)(12,25)(13,18)(14,19)(15,20)(16,23)(17,27)(22,30)(24,31)(26,34)(28,32)(29,33)(35,38)(36,40)(37,39) involution — undirected(3,7)(5,8)(9,11)(10,16)(12,22)(13,28)(14,23)(15,24)(17,30)(18,21)(19,31)(20,32)(25,39)(26,36)(27,38)(29,37)(33,40)(34,35) involution — undirected(1,2)(3,8)(4,6)(5,7)(9,12)(10,17)(11,22)(13,27)(14,29)(15,26)(16,30)(18,34)(19,25)(20,33)(21,35)(23,37)(24,36)(28,38)(31,39)(32,40) involution — undirected(12,26)(17,33)(22,36)(25,34)(27,29)(30,40)(35,39)(37,38) involution — undirected(9,13,15,14)(10,18,20,19)(11,23,24,28)(12,27,26,29)(16,31,32,21)(17,34,33,25)(22,37,36,38)(30,39,40,35)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.