g = ;

coordRules=Thread[VertexList[g]->(VertexCoordinates/.AbsoluteOptions[g,VertexCoordinates])];

showCores[cores_]:=Show[Append[Graphics/@Table[Join[{Hue[1-k/(Length[cores]+1),.3,.7],Thickness[0.14],CapForm["Round"]},Line[(List@@#)/.coordRules]&/@EdgeList[Subgraph[g,Join@@cores[[k]]]]],{k,1,Length[cores]}],HighlightGraph[g,{},VertexStyle->EdgeForm[{White,Opacity[1]}],EdgeStyle->Directive[Thick,Opacity[1],White]]],ImageSize->500];

showCores[Table[KCoreComponents[g,k],{k,1,3}]]