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