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