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