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