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