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