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