One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,14)(8,18)(9,12)(10,13)(11,15)(16,19)(17,20) involution — undirected(1,2)(3,4)(5,6,9,18,10,13,8,12)(7,11,16,20,17,19,15,14)(2,4) involution — undirected(2,4)(5,6)(7,11)(8,12)(9,18)(10,13)(14,15)(16,20)(17,19) involution — undirected(5,7,8,15,10,17,9,16)(6,11,12,14,13,19,18,20)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.