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