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