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