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