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