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