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