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