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