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