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