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