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