if you are using Maximenu Pro, you can change that in the styling interface
else you can use this css code to manage it
Code:
div#main-menu ul.maximenuck li.level2.parent > a::after {
border-color: transparent transparent transparent red !important;
}
div#main-menu ul.maximenuck li.level2.parent:hover > a::after {
border-color: transparent transparent transparent blue !important;
}
(color to be adapted)
