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