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