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