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