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