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