Please update to the newest version and custom the CSS style.
<style type="text/css">
.f .radiobutton {
border-color: #000;
}
.f .radiobutton .radiobutton-inner{
background: #000;
}
.f .textbox-label{
color: #000;
}
.f .radiobutton-checked{
border-color: blue;
}
.f .radiobutton-checked .radiobutton-inner{
background: blue;
}
.f .textbox-label-checked{
color: blue;
}
</style>
<form id="ff" class="f">
<div style="margin-bottom:20px">
<input class="easyui-radiobutton" name="fruit" value="Apple" label="Apple:">
</div>
...
</form>