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