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