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