This code will add a rendering section to the layer to render shape using Color (or other properties like OutlineWidth)  based on query value 

Layer.ParamsList.Add
Layer.Params.Query = "VELOCITY < 30"
Layer.Params.Marker.Color = YELLOW

Layer.ParamsList.Add
Layer.Params.Query = "VELOCITY BETWEEN 30 and 70"
Layer.Params.Marker.Color = GREEN

Layer.ParamsList.Add
Layer.Params.Query = "VELOCITY > 70"
Layer.Params.Marker.Color = RED