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