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