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