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