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