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