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