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