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