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