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