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