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