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