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)(15,24)(16,21)(17,23)(18,20)(19,27)(22,26)(25,28) involution — undirected(6,9)(10,12)(14,20)(21,24)(22,28)(23,27) involution — undirected(1,2,3,4)(13,15,18,16)(14,21,20,24)(17,26,19,25)(22,23,28,27)(13,16,18,15)(14,22,20,28)(17,26,19,25)(21,23,24,27)(5,7,8,11)(6,10,9,12)(13,17,18,19)(14,23,20,27)(15,25,16,26)(21,22,24,28)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.