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