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