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