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