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