By default, layers created with the TLspShapeLayerBuilder use an orange color to indicate selected objects:

selection style colors

You can change that selection color by installing your own ILspStyler for the selection TLspPaintRepresentationState. To do so, you can start from the TLspSelectionStylerBuilder class, for example: 

//Create the style for the body. Here we use a single ALspStyle,
//but it also works for an ALspStyler
ALspStyle iconStyle = TLspIconStyle.newBuilder()
                                   .build();

//Use the TLspSelectionStylerBuilder to create a selection styler
ALspStyler selectionStyler = TLspSelectionStylerBuilder.newBuilder()
                                                       .styles(iconStyle)
                                                       .outlineColor(Color.BLUE)
                                                       .build();

//Install the selection styler on the layer
TLspLayer layer = TLspShapeLayerBuilder.newBuilder()
                                       .bodyStyler(TLspPaintState.REGULAR, iconStyle)
                                       .bodyStyler(TLspPaintState.SELECTED, selectionStyler)
                                       .model(model)
                                       .build();