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