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)(13,14,19,23)(15,24,16,27)(17,22,18,21)(20,25,28,26)(2,4)(7,8)(10,11)(13,15)(14,20)(16,19)(17,25)(18,26)(21,27)(22,24)(23,28) involution — undirected(5,7,9,8)(6,10,12,11)(13,16,19,15)(14,20,23,28)(17,26,18,25)(21,27,22,24)(5,8,9,7)(6,11,12,10)(13,17,19,18)(14,21,23,22)(15,25,16,26)(20,27,28,24)(6,12)(10,11)(13,17,19,18)(14,21,23,22)(15,25,16,26)(20,27,28,24)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.