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