saas-one/frontend/operation-web/overrides/grid/column/CheckColumn.scss

.x-grid-switchcolumn, .x-grid-switchcolumn-checked {
    display: inline-block;
    width: 34px;
    height: 21px;
}
.x-grid-switchcolumn {
    background: url(get-resource-path('images/grid/uncheck.png')) 0 0 no-repeat;
    cursor: pointer;
}
.x-grid-switchcolumn-checked {
    background: url(get-resource-path('images/grid/check.png')) 0 0 no-repeat;
}