MOUNT VERNON - Shawna Antoine, 12, prepared to paint a rainbow mural across a wall in Graham Elementary School yesterday.

"They will see a beautiful school," she said of what students will think of the finished product. "They will think someone cares about them."

Shawna is a member of Young Heroes, a branch of City Heroes, a Bronx-based youth community-service program, which is now extending its roots in Mount Vernon. The organization is funded primarily through corporations and private donors.

Yesterday marked "Make A Difference Day" for the group and included painting ocean, cloud and letter murals and creating bookshelves and flower boxes for Graham Elementary. A school improvement project like yesterday's could cost an estimated $30,000, organizers said.

More than 100 volunteers, including 70 from City Heroes, showed up to paint, hammer and build. Volunteers also came from Nepperhan Community Center in Yonkers and Mount Vernon Heights Congregational Church.

"Everyone has the hope that to bring revitalization to the school, it starts with the walls," said organizer Kate Frasca of City Heroes.

Young Heroes began at Graham Elementary School last year and attracted 20 children, said program leader Kevin Moore, a sixth-grade teacher at Graham.

This year, two dozen more students have shown interest. Every Saturday, the children travel to the South Bronx for activities such as visiting the elderly in nursing homes, setting up beds for the homeless or attending an anti-violence march.

"The children I had last year, it was a growing experience, and they took the spirit of service and brought it back to the school," Moore said. "The word has spread; it's infectious."

Patrick Bail, an 11-year-old student at A.B. Davis Middle School in Mount Vernon, joined Young Heroes last year and enjoys spending his Saturdays volunteering with 10 classmates.

Patrick laid out a tarp on the floor yesterday and got ready to paint a mural that read "Diversity."

Volunteering gives balance to his academics and has made him more "kind" and "generous," he said.

"I think it could help me get into college," said Patrick, who has his sights set on Yale University.

Graham Elementary School Principal Natasha Hunter-McGregor said yesterday's murals will add to the ones created last year when she first became principal.

The paintings, which have turned empty walls into pieces of art, boost morale among students and teachers, Hunter-McGregor said.

"When I walked into these buildings, I didn't feel a sense of warmth," she said. "It's not just the murals; it's what goes into it. Now, when I walk through the hallways, I see the faces of my children."

Reach Theresa Juva at tjuva@lohud.com or 914-694-5012.