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