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