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