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