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