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