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