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