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