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