You can use the ngClass to use conditional class to your component. When you have no selectedColor, you set a class that will have the configurations you need to achieve that look like your example.

Example: Html:

<input class="color-input" [ngClass]="{ 'no-color': selectedColor == null }" [(colorPicker)]="selectedColor"
       [style.background]="selectedColor" (cpSliderDragEnd)="changeColor()">

CSS:

.no-color {
   background: white;
   background-image: 'path-to-image';
.
.
.
}