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