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