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