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