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)(11,16)(15,20)(17,19) involution — undirected(1,2)(3,4)(5,6,9,18,10,13,8,12)(7,11,17,20,15,19,16,14)(2,4)(7,15)(11,19)(14,20)(16,17) involution — undirected(2,4)(5,6)(7,11)(8,12)(9,18)(10,13)(14,16)(15,19)(17,20) involution — undirected(5,7,8,16,10,15,9,17)(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.