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